Frictional gearing for dental machines.



No. 733,807. PATENTED JULY 14,1903. L. L. BOSWORTH.

FRIGTIONAL GEARING FOR DENTAL MACHINES.

APPLIOATION PILED JAN; 21, 1903.

2 SHEETS-SHEET 1.

, N0 MODEL.

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Era Y7, ATTY PATE'N'I'BD JULY 14, 1903.

L. L. BOSWORTH. FRIOTIONAL GEARING FOR DENTAL MACHINES.

APPLICATION FILED JAN. 21, 1903.

2 SHEETS-SHEET 2.

H0 MODEL.

UNITED STATES Patented July 14, 1903.

PATENT ()FFICE.

LUTHER L. BOSWORTH, OF CLEVELAND, OHIO.

SPECIFICATION forming part of Letters Patent N 0. 733,807, dated July 14, 1903.

' Application filed January 21,1908; Serial No. 139.905. (No model.)

To all whom, it mayconccrn:

Be it known that I, LUTHER L. BOSWORTH, a citizen of the United States, residing at Cleveland, in the county of Ouyahoga and State of Ohio, have invented certain new and useful Improvements in Frictional Gearing for Dental'Machines; and I do declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to frictional gearing for dental machines; and the invention consists in the construction and combination of parts, substantially as shown and described, and particularly pointed out in the claims.

In the accompanying drawings, Figure 1 is a perspective elevation of the machine and its connections complete. Fig. 2 is an enlarged detail of the standard for supporting the flexible driving-shaft for the tool, and Fig. 3 is an enlarged perspective plan view of the top of the cabinet portion of the machine. Fig. 4 is a vertical sectional elevation of the machine substantially on the plane of the frictionnvheetshaft, and Fig. 5 is a vertical sectional elevation at right angles to Fig. 4. Fig. 6 is a horizontal central sectional plan of the driving-disk and the dead-center brake connected therewith and showing the friction-wheel in working relation therewith, as hereinafter fully described. Fig. 7 is an enlarged plan of the speed-regulator or foot controlling-yoke for the machine. I

The machine thus shown is designed especially for dental use, though not necessarily limited thereto, and is comparatively small in size and adapted to be conveniently moved about upon the floor of a room to one position or another, as may be desirable or convenient, and the machine comprises a suitable motor, such as an electric motor, as its source of power and means for graduating the speed of the machine and for stopping the same entirely at the will of the operator. To these ends, A represents the main frame or stand, which ordinarily is about three feet high and has a box or cabinet aat its top, within which is contained most of the operating mechanism. This mechanism. comprises an electric motor M on a drive-shaft S,

carrying a friction-disk D, and the motor has electrical connection by means of a wire strand F, which has sufficient slack to permit the machine to be moved here and there over the floor and is provided with a suitable weight 2 to take up the slack, relatively as shown in Fig. l, and keep the strand or cord out of the way.

' Power is communicated from disk D to friction-wheel W by friction contact between them, and the said wheel preferably has a rubber ring 5 for making engagement with the disk. The wheel W has a hub 7, sleeved to slide freely upon shaft G, and upon the hub '7 is secured a forked con-trolling arm or lever-L, pivoted in its forked extremities on short lugs 9 on a collar on said hub 7, on which the lever L has a rocking movement as it is operated to slide the wheel to and fro upon its shaft. trolled by a rod R, pivoted at 10 on stand A and adapted to be vibrated on this pivot through speedregulating foot-yoke Y,accord- Said lever is in turn con-.

ing as the machine is to be run faster or slower.

Presumably while the machine is being.

chine wheneverdesired, and for this purpose I provide a brake 0, set centrally into disk D and flush therewith andhaving a spindle 16 projecting into its shaft S, which has a bore in its end and carriesahard-metal bearing-block 12 for the bearing-point 13 of said spindle. Said brake has a relatively small disk-shaped head 14: even with outer surface of disk D and free in respect thereto and also practically out of friction contact with shaft S, so that when friction-wheel Wis carried to the center of disk D to stop operations the said wheel bears upon the face or surfaces of the said brake and is wholly out of contact with disk D. Thus I can instantly stop rotation of wheel \V, while shaft S and disk D continue to run, and this will of course also effect instant stoppage of flexible drill or tool shaft H, which carries the working instrument at its free end. A detainingscrew engages an annular groove in the spindle 16 of the brake and con fines thebrake in working position.

It will be noticed thatthe cabinet or casing a of the stand has asubstantially H-shaped slotted formation in its top in which there are two parallel slots 17 and a transverse slot 18, with a circular opening 19 in its middle, in which is supported standard N for shaft H. The belt or cord 3, which passes over sheaves 4 and h, passes through the slots 17, which afford room for the said belt or cord to move back and forth as the wheel is moved here and there on shaft G, and by having the trans verse slot 18 I am enabled to use a belt or cord that is endless or which is made up for this use without any break or end connections. It is obvious that by having such a cord I can place the same, say, over the sheave h and then carry it up through slot 19 into slots 17 and thence up over sheave H above. Sheave h is fixed on the extremity of shaft II and is supported by standard N, adjustable extensions 20 thereon, and arm 23 on said extension, in which shaft II is rotatable. Any slack in the belt is conveniently taken up by this construction through the extension 20, which is socketed in standard N and has a lug 21 upon its side, adapted to engage in any one of the series of notches 22 upon opposite sides of said slot, so that a very fine graduation of adjustment for extension 20 can be had.

A slot a is formed in the bottom ofcabinet a for the free movement of rod R, and springs 25 from opposite sides hold said rod normally in a central position, which brings frictionwheel W to the dead-center of friction-disk D over or upon brake O, and said springs will assert themselves and cause this to occur the instant the rod R is released from control by the foot of the operator.

The speed-regulating yoke Y comprises a T-shaped rigid member on the lower end of rod R, and the yoke itself is of flat spring metal, preferably shaped in the form of the the letter W, fastened at its ends to member R. The spring-metal yoke conforms perfectly to the shoe and gives direct control without loss of motion. With this yoke the operator is enabled to stand on both feet while doing his work and yet at the same time control the machine by moving his foot right or left, with the heel of his shoe as the pivot of movement.

The support for shaft G and friction-wheel W thereon is adjustably mounted upon the base-board a and is held in place by screws and thumb-nuts. A threaded screw and nuts connect the top of the supports with the motor, and it is by this means that the varying pressure of the friction-wheel W against disk D and brake C is obtained. Wear upon the rubber ring can be thus taken up at any time.

What I claim is 1. The friction-disk and the flat-surfaced brake in the center thereof, in combination with a shaft parallel to the face of the disk, a friction-wheel and sheave slidable together on said shaft, and means to automatically hold the said friction-wheel on said brake, substantially as described.

2. The combination of the friction-wheel and a shaft carrying the same, and a vibratory rod to control the position of the wheel on its shaft, in combination with a frictiondisk engaged by said wheel, a power-driven shaft carrying said disk, a brake for said wheel-support in one end of said shaft and having its face flush with said disk, and springs to automatically carry the said wheel to the dead-cen ter of said disk over said brake, substantially as described.

Witness my hand to the foregoing specification this 26th day of December, 1902.

LUTHER L. BOSVVORTH.

Witnesses:

R. B. MOSER, R. ZBORNEK. 

